TNF and rheumatoid arthritis: Among activated immune cells in RA, macrophages, which produce TNF-α, IL-6 and IL-1β (Zheng et al., 2014; Clavel et al., 2016) and tissue-degrading enzymes in the inflammatory infiltrate synovial sublining and at the pannus-cartilage interface (Davignon et al., 2013; Yeo et al., 2016), are central players in the pathogenesis (Szekanecz and Koch, 2007) and are an ideal target for the treatment of RA (Davignon et al., 2013).